In recent years, silicon carbide has been increasingly employed as a material for a semiconductor device such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) in order to allow a higher breakdown voltage, lower loss and the use in a high-temperature environment and the like of the semiconductor device. Silicon carbide is a wide band gap semiconductor having a band gap wider than that of silicon which has been conventionally and widely used as a material for a semiconductor device. By employing the silicon carbide as a material for a semiconductor device, therefore, a higher breakdown voltage, lower on-resistance and the like of the semiconductor device can be achieved. A semiconductor device made of silicon carbide is also advantageous in that performance degradation is small when used in a high-temperature environment as compared to a semiconductor device made of silicon.
A silicon carbide substrate used to manufacture a semiconductor device is formed by slicing a silicon carbide ingot formed by a sublimation method, for example. Japanese Patent Laying-Open No. 2009-105127 (PTD 1) describes a method of manufacturing a silicon carbide wafer. According to this method of manufacturing a silicon carbide wafer, a surface of a workpiece sliced and cut from an ingot of SiC is ground and polished, so that the surface of the workpiece is smoothed into a mirror surface. After the surface of the workpiece is smoothed, a backside surface of the workpiece is ground.